Anyone with severe allergies knows that an epinephrine auto-injector can be the difference between life and death. With approximately two and a half million epinephrine auto-injectors (such as EpiPens and Auvi-Qs) in circulation, my colleagues and I at Nationwide Children's Hospital want to ensure that people know how to administer them appropriately — you could save a life.

A new law signed by President Barack Obama on Nov. 13 last year provides states with financial incentives to pass laws that allow schools to stock epinephrine, and to treat children who do not have a prescription for the drug. As a result, more people will be administering auto-injectors for the first time.

It is not hard to use one, you just need to take action quickly. In fact, the most common reason associated with death from severe allergies is waiting too long to administer epinephrine.

The good news is that instructions are written and pictured on each auto-injector. One type of auto-injector even gives verbal instructions.

Here's what you will need to know to correctly use an auto-injector:

1. Prepare the device

Pull off the safety cap. Make a fist around the syringe so the tip is pointing down. But there's a warning: DO NOT PUT YOUR THUMB ON THE ORANGE TIP. The needle comes out of the orange tip.

2. Inject the medicine

While you do not need to apply excessive force, you will swing your arm a bit to inject the contents of an auto-injector (you need to provide enough force that the needle deploys from the auto-injector tip and delivers its contents directly into thigh muscle). First, hold the orange tip near the patient's outer thigh to position the device at a 90-degree angle (needle-tip straight down), then swing the auto-injector against the patient's outer thigh and press firmly against it until you hear a click. Hold the auto-injector against the thigh for 10 seconds. Then, remove the auto-injector from the thigh and massage the injection site for 10 seconds. You can leave the patient's pants on if necessary; the device will work right through them.? [8 Strange Signs You're Having an Allergic Reaction ]

3. Get emergency medical help

Always call 9-1-1 after using epinephrine. The medicine may start to wear off or the reaction may come back. You can repeat the dose in 5 minutes if the child is not improving. Give the used epinephrine injector to a health care provider and ask for a refill right away if needed.

A few other things to note: Inhalers, such as albuterol and antihistamines (such as Benadryl), are not enough to treat severe allergic reactions. They can be given after epinephrine is used, if available. When in doubt, give epinephrine!

Do not store an auto-injector in a refrigerator or a hot car. It should be kept at room temperature. The liquid medicine in the pen should be clear. If it is discolored or has floating specks, get a new pen.

There is more than one type of auto-injector that delivers epinephrine. For more information about how to use an EpiPen, you can watch this video. To see how to use an Auvi-Q, watch this video.

The views expressed are those of the author and do not necessarily reflect the views of the publisher. This version of the article was originally published on LiveScience.